Destruction of carbon tetrachloride in the presence of hydrogen-supplying compounds with ionisation and catalytic oxidation: Part 2. Methane as hydrogen font

The performance of methane (CH₄) as hydrogen donor molecule for the deep and clean oxidation of tetracloromethane (CCl₄) has been experimented. The oxidation of CCl₄–CH₄ admixtures were performed by catalytic combustion with and without pre-catalytic actions (i.e. ionisation/ozonisation) over manganese oxide based catalyst. The extent of CCl₄ and CH₄ combustion was controlled by quantitative determinations of both CO₂ and HCl formed and of CCl₄ and CH₄ converted. Experiments were performed in the 100–500 °C reaction interval in a continuous reaction line at laboratory scale. Fixed CCl₄ concentration (2000 ppmv) with/without CH₄ addition to air constituted the feed. Methane was added to the feedstream in variable concentration (1000–3000 ppmv), the obtained organic mixtures had H/Cl atomic ratios (R_H/Cl) from 0.5 to 1.5. Comparing the tests of ionisation/ozonisation (I/O) of pure CCl₄ streams and CCl₄–CH₄ admixtures, the efficiency of the hydrogen donor role of CH₄ was evidenced. The residue CH₄ concentration was not affected by the residence time (14–42 s) in the ionisation reactor while the residue concentration of CCl₄ decreased by increasing it. A first-order rate equation in CCl₄ concentration was found to represent the ionisation process both in the absence and in the presence of hydrocarbon. On the manganese oxide catalyst, CCl₄ catalytic combustion (CC) was not remarkably influenced by CH₄ presence. CCl₄ destruction by catalytic combustion assisted with ionisation (IOCC) gave rise to higher HCl yield in comparison with conventional combustion. The HCl formation increased with increasing the R_H/Cl value both in the I/O and IOCC experiments, while the CO₂ formation lightly decreased for high R_H/Cl in the CC and IOCC experiments due to incomplete oxidation of CH₄.     

Homology modeling of NR2B modulatory domain of NMDA receptor and analysis of ifenprodil binding

NMDA receptors are glutamate-gated ion channels (iGluRs) that are involved in several important physiological functions such as neuronal development, synaptic plasticity, learning, and memory. Among iGluRs, NMDA receptors have been perhaps the most actively investigated for their role in chronic neurodegeneration such as Alzheimer's, Parkinson's, and Huntington's diseases. Recent studies have shown that the NTD of subunit NR2B modulates ion channel gating through the binding of allosteric modulators such as the prototypical compound ifenprodil. In the present paper, the construction of a three-dimensional model for the NR2B modulatory domain is described and docking calculations allow, for the first time, definition of the ifenprodil binding pose at an atomic level and fully explain all the available structure-activity relationships. Moreover, in an attempt to add further insight into the ifenprodil mechanism of action, as it is not completely clear if it binds and stabilizes an open or a closed conformation of the NR2B modulatory domain, a matter, which is fundamental for the rational design of NMDA antagonists, MD simulations followed by an MM-PBSA analysis were performed. These calculations reveal that the closed conformation of the R1-R2 domain, rather than the open, constitutes the high affinity binding site for ifenprodil and that a profound stabilization of the closed conformation upon ifenprodil binding occurs. Thus, for a rational design and/or for virtual screening experiments, the closed conformation of the R1-R2 domain should be taken into account and our 3D model can provide valuable hints for the design of NR2B-selective antagonists.     

Optimization-oriented design of free-running and tunable microwave oscillators by fully nonlinear CAD techniques (invited article)

The article reviews the application of optimization techniques, in conjunction with the methods of harmonic-balance simulation, to the nonlinear design of free-running and tunable microwave oscillators. The purpose is to give an in-depth treatment of many different aspects of the practical oscillator design problem, and of their formulation in terms of numerical optimization. This includes free-running and tunable oscillators, with both discrete (multiple-cavity) and continuous tuning. Conventional specifications on electrical performance are extended to include near-carrier phase noise, steady-state stability, and tuning linearity in the VCO case. The problem of designing oscillators integrated with other nonlinear subsystems to build up multifunctional modules is also addressed. Several examples of application to typical engineering problems are provided. © 1997 John Wiley & Sons, Inc. Int J Microwave Millimeter-Wave CAE 7: 52–74, 1997.     

Conformal,Ultra-thin Skin-Contact-Actuated Hybrid Piezo/Triboelectric Wearable Sensor Based on AlN and Parylene-Encapsulated Elastomeric Blend

Flexible electronics based on piezoelectric/triboelectric devices is an attractive technology for human sensing. Their hybridization overcomes the limitations of single components, resulting in compliant skin sensors with enhanced performances and applicability. Such hybrid devices are typically based on wide-area scarcely durable polymers or lead-containing piezoelectric materials; they are often not biocompatible and poorly skin-adaptable, lacking in multifunctionality. In this work, a novel compliant, conformal hybrid piezoelectric-triboelectric ultra-thin wearable sensor made of biocompatible materials is reported. The device is in contact with skin through an ultra-soft patch covered on both sides by a thin friction parylene film. Its working principle is unprecedently based on three simultaneous, complementary and mutually enhancing effects: piezoelectric, skin-contact-actuation, and piezo-tribo hybrid contact. The device can detect, with high sensitivity and wide measurement range, both the impulsiveness of sudden motions and the slower micro-friction phenomena due to skin deformations, ensuring a stable and repeatable identification of bio-signals typical of body movements. The device multifunctionality is shown for identifying gait walking, distinguishing hand gestures with a 5-sensor system on the hand back, and monitoring human joints motions (neck, wrist, elbow, knee, ankle). The assessed energy harvesting capabilities demonstrate the suitability for fabrication of more complex self-powered sensing systems.     

Effects on speed and safety of point-to-point speed enforcement systems: Evaluation on the urban motorway A56 Tangenziale di Napoli

In this paper, we evaluated the effects on speed and safety of the point-to-point (P2P) speed enforcement system activated on the urban motorway A56 in Italy. The P2P speed enforcement is a relatively new approach to traffic law enforcement that involves the calculation of the average speed over a section. To evaluate the speed effects, we performed a before–after analysis of speed data investigating also effects on non-compliance to speed limits. To evaluate the safety effects, we carried out an empirical Bayes observational before-and-after study.     

Small Molecule Membrane Transporters in the Mammalian Podocyte: A Pathogenic and Therapeutic Target

The intriguingly complex glomerular podocyte has been a recent object of intense study. Researchers have sought to understand its role in the pathogenesis of common proteinuric diseases such as minimal change disease and focal segmental glomerular sclerosis. In particular, considerable effort has been directed towards the anatomic and functional barrier to macromolecular filtration provided by the secondary foot processes, but little attention has been paid to the potential of podocytes to handle plasma proteins beyond the specialization of the slit diaphragm. Renal membrane transporters in the proximal tubule have been extensively studied for decades, particularly in relation to drug metabolism and elimination. Recently, uptake and efflux transporters for small organic molecules have also been found in the glomerular podocyte, and we and others have found that these transporters can engage not only common pharmaceuticals but also injurious endogenous and exogenous agents. We have also found that the activity of podocyte transporters can be manipulated to inhibit pathogen uptake and efflux. It is conceivable that podocyte transporters may play a role in disease pathogenesis and may be a target for future drug development.